‘TEMPLETON—EFrFect oF LATE Frost oN Woop oF ACER. II 
medullary rays. In this case the zone of parenchyma also con- 
stituted a line of weakness in the wo 
It is noticeable also that in no case is a radial fracture in the 
outer portion of the wood in line with one in the inner portion, 
due, no doubt, to the break in the continuity of the medullary 
rays previously referred to. 
Since the medullary rays are the routes, par excellence, along 
which water and food materials in solution move radially in the 
wood, the question arises as to whether the passage of these fluids 
was affected by the interruption of the medullary rays. 
It is well known that in Summer, starch is stored in the 
medullary rays and wood parenchyma, after having been con- 
veyed to these situations in the form of sugar. If the passage of 
sugar had been restricted, this would be apparent by an examina- 
tion of the radial distribution of starch. A narrow transverse 
strip passing through the centre was therefore removed from 
each cut, and these were placed for some hours in a solution of 
iodine. The result is shown in Plate CXCIII.* The wood of 
strips B-G is normal, and the maximum amount of starch in 
each strip, judging from the depth of the stain, is found in the 
outermost wood-rings, with a gradual diminution towards the 
centre. In strip A there is a sudden, and very well marked de- 
crease in the amount of starch in the wood within the abnormal 
wood-ring (a), which indicates, in a very convincing manner, that 
the inward passage of sugar had been very considerably re- 
stricted, and the internal economy of the tree consequently 
affected. 
In conclusion, I wish to express my indebtedness to the late 
Sir Isaac Bayley Balfour, for placing the material for 
investigation at my disposal, and to Mr R. L. Harrow, Head 
Gardener, Royal Botanic Garden, for his care in carrying out the 
details of felling. 
black areas at b and ¢ are not indicative of presence of starch, but 
are discolourations in the wood, due to a knot, and decayed pith, respectiv ely, 
